CUDA Compute Device says "(dislplay)" beside it. What does that mean?
If your GPU is connected to a monitor (or multiple ones), then you'll see the (display) notice. That only means that the GPU is also being used to display images on a monitor.

Blender will still use it to render, just know that some of the resources of the GPU are going to be used to refresh the screen(s). If you have multiple GPUs you might see the difference.



In this example both GPUs are used for rendering, but one of them is using some resources to feed my monitors, while the other is used exclusively to render.